Enantioselective Radical Reactions Using Chiral Catalysts

Chemical Reviews, Год журнала: 2022, Номер 122(6), С. 5842 - 5976

Опубликована: Янв. 24, 2022

Benefiting from the impressive increase in fundamental knowledge, last 20 years have shown a continuous burst of new ideas and consequently plethora catalytic methods for enantioselective radical reactions. This review aims to provide complete survey progress achieved over this latter period. The first part focuses on use chiral organocatalysts, these include catalysts covalently linked substrate those that interact with by weaker interactions like hydrogen bonds. second is devoted transition-metal redox catalysis which organized according increasing atomic number first-row transition metals (Ti, Cr, Fe, Mn, Co, Ni, Cu). Bioinspired manganese- iron-mediated hydroxylations oxidations are also discussed. A specific section dedicated reactivity Ru, Rh, Ir complexes as Lewis acids special focus at metal. Absorption photons result different events such energy transfer, single-electron hydrogen-atom transfer facilitating formation radicals. Organocatalysis has been successfully combined photocatalysts, opened pathways enlarging precursors available. merger photocatalysis organo- or metalla-photocatalysis brought novelty allowed discovery large original transformations. enzyme-catalyzed reactions involving intermediates largely benefit visible-light irradiation included review. provides comprehensive inventory goal detailing reaction mechanisms involved transformations any nonspecialist could find their own creativity invent yet unknown applications.

Язык: Английский

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Nitrene transfer catalysts for enantioselective C–N bond formation

Nature Reviews Chemistry, Год журнала: 2021, Номер 5(8), С. 580 - 594

Опубликована: Июнь 28, 2021

Язык: Английский

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Transition Metal Catalysis Controlled by Hydrogen Bonding in the Second Coordination Sphere

Chemical Reviews, Год журнала: 2022, Номер 122(14), С. 12308 - 12369

Опубликована: Май 20, 2022

Transition metal catalysis is of utmost importance for the development sustainable processes in academia and industry. The activity selectivity complexes are typically result interplay between ligand properties. As can be chemically altered, a large research focus has been on development. More recently, it recognized that further control over achieved by using “second coordination sphere”, which seen as region beyond direct sphere center. Hydrogen bonds appear to very useful interactions this context they have sufficient strength directionality exert second sphere, yet hydrogen dynamic, allowing fast turnover. In review we highlighted several key features bonding summarized use program sphere. Such bridging two ligands coordinated center effectively lead supramolecular bidentate ligands. addition, used preorganize substrate Both strategies catalysts with superior properties variety catalyzed transformations, including (asymmetric) hydrogenation, hydroformylation, C–H activation, oxidation, radical-type photochemical reactions.

Язык: Английский

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Highly Regio- and Enantioselective Reductive Coupling of Alkynes and Aldehydes via Photoredox Cobalt Dual Catalysis

Journal of the American Chemical Society, Год журнала: 2021, Номер 143(19), С. 7306 - 7313

Опубликована: Май 5, 2021

A Co-catalyzed highly regio- and enantioselective reductive coupling of alkynes aldehydes has been developed under visible light photoredox dual catalysis. variety enantioenriched allylic alcohols have obtained by using unsymmetrical internal commercially available catalyst, chiral ligand, reagents. It is noteworthy that this approach considerable advantages, such as excellent (>95:5 for >40 examples), stereo- (up to >95:5 E/Z), enantioselectivity (92-99% ee, >35 examples) control, mild reaction conditions, broad substrate scope, good functional group compatibility, making it a great improvement alkyne-aldehyde reactions.

Язык: Английский

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Metalloradical Catalysis: General Approach for Controlling Reactivity and Selectivity of Homolytic Radical Reactions

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(20)

Опубликована: Март 13, 2024

Abstract Since Friedrich Wöhler's groundbreaking synthesis of urea in 1828, organic over the past two centuries has predominantly relied on exploration and utilization chemical reactions rooted two‐electron heterolytic ionic chemistry. While one‐electron homolytic radical chemistry is both rich fundamental reactivities attractive with practical advantages, synthetic application been long hampered by formidable challenges associated control reactivity selectivity high‐energy intermediates. To fully harness untapped potential for synthesis, there a pressing need to formulate radically different concepts broadly applicable strategies address these outstanding issues. In pursuit this objective, researchers have actively developing metalloradical catalysis (MRC) as comprehensive framework guide design general approaches controlling stereoselectivity reactions. Essentially, MRC exploits metal‐centered radicals present open‐shell metal complexes catalysts activation substrates generate metal‐entangled key intermediates govern reaction pathway stereochemical course subsequent catalytic processes. Different from conventional transition complexes, operates through utilizing stepwise mechanisms.

Язык: Английский

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Cobalt-Catalyzed Intermolecular C–H Amidation of Unactivated Alkanes

Journal of the American Chemical Society, Год журнала: 2021, Номер 143(13), С. 5191 - 5200

Опубликована: Март 29, 2021

Alkanes are an abundant and inexpensive source of hydrocarbons; thus, development new methods to convert the hydrocarbon feedstocks value-added chemicals is high interest. However, it challenging achieve such transformation in a direct selective manner mainly due intrinsic inertness their C–H bonds. We herein report tailored Cp*Co(III)(LX)-catalyzed efficient site-selective intermolecular amidation unactivated hydrocarbons including light alkanes. Electronic modulation cobalt complexes led enhanced efficiency, these effects were theoretically rationalized by FMO analysis presupposed nitrenoid species. Under current protocol, secondary bond selectivity was observed various nonactivated alkanes reverse tertiary preference, which attributed steric demands system that imposes difficulties accessing Experimental computational studies suggested putative triplet Co nitrenoids transferred bonds via radical-like hydrogen abstraction pathway.

Язык: Английский

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Enantioselective Access to Spirolactams via Nitrenoid Transfer Enabled by Enhanced Noncovalent Interactions

Journal of the American Chemical Society, Год журнала: 2021, Номер 143(17), С. 6363 - 6369

Опубликована: Апрель 22, 2021

Described herein is the Ir-catalyzed enantioselective access to chiral spirolactam products via nitrenoid transfer aromatic ipso-carbons. The key strategy for precise stereocontrol enhance secondary attractive and repulsive interactions between catalyst substrates by introduction of a traceless O-silyl achiral auxiliary, thus effectively differentiating two prochiral faces arenol-derived 1,4,2-dioxazol-5-one substrates.

Язык: Английский

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Metal-Catalyzed Enantioconvergent Transformations

Chemical Reviews, Год журнала: 2023, Номер 123(20), С. 11817 - 11893

Опубликована: Окт. 4, 2023

Enantioconvergent catalysis has expanded asymmetric synthesis to new methodologies able convert racemic compounds into a single enantiomer. This review covers recent advances in transition-metal-catalyzed transformations, such as radical-based cross-coupling of alkyl electrophiles with nucleophiles or alkylmetals and reductive two mainly under Ni/bis(oxazoline) catalysis. C–H functionalization can be performed an enantioconvergent manner. Hydroalkylation alkenes, allenes, acetylenes is alternative reactions. Hydrogen autotransfer been applied amination alcohols C–C bond forming reactions (Guerbet reaction). Other metal-catalyzed involve addition allylic systems carbonyl compounds, propargylation phenols, 3-bromooxindoles, allenylation allenolates propargyl bromides, hydroxylation 1,3-dicarbonyl compounds.

Язык: Английский

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Biomimetic asymmetric catalysis

Science China Chemistry, Год журнала: 2023, Номер 66(6), С. 1553 - 1633

Опубликована: Апрель 25, 2023

Язык: Английский

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Chiral Iron Porphyrins Catalyze Enantioselective Intramolecular C(sp³)−H Bond Amination Upon Visible‐Light Irradiation

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(19)

Опубликована: Янв. 30, 2023

Iron-catalyzed asymmetric amination of C(sp3 )-H bonds is appealing for synthetic applications due to the biocompatibility and high earth abundance iron, but examples such reactions are sparse. Herein we describe chiral iron complexes meso- β-substituted-porphyrins that can catalyze intramolecular aryl arylsulfonyl azides afford indolines (29 examples) benzofused cyclic sulfonamides (17 examples), respectively, with up 93 % ee (yield: 99 %) using 410 nm light under mild conditions. Mechanistic studies, including DFT calculations, reveal Fe(NSO2 Ar) intermediate generated in situ photochemical conditions reacts bond through a stepwise hydrogen atom transfer/radical rebound mechanism, enantioselectivity arising from cooperative noncovalent interactions between unit peripheral substituents porphyrin scaffold.

Язык: Английский

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